Tuning dial for radio receiving sets



March 29, 1938. A. s. WELLS El AL TUNING DIAL FOR RADIO RECEIVING SETS Filed July 1, 1936 6 Sheets-Sheet 1 March 29, 1938. A. s. WELLS ET AL TUNING DIAL F-OR RADIO RECEIVING SETS Filed July 1, 1956 6 Sheets-Sheet 2 Mmh 29, 1938. A. s. WELLS ET AL. 2,112,745

TUNING DIAL FOR RADIO RECEIVING SETS Filed July 1, 1936 e Sheets-Sheet s 7 47 '77 6 i 77 19 .1 QT

I! n =mm f /z I I I r w l I A 11/ Fri" in] hi) I H J i 'rz ii 15/ /5;

March 29, 1938.

A. s. WELLS ET AL 2,112,745 TUNING DIAL FOR RADIO RECEIVING SETS Filed July 1, 1936 6 Sheets-Sheet 4 March 129,, .1938 A. :s. WELLS ETLAL TUNING DIAL FOR RADIO LREQEIVLNG SETS Filed July '1, v1.936

VENEZUELA EERMRNY March 29, 1938. A. s. WELLS ET AL 'TUNING DIAL FOR RADIO RECEIVING SETS Filed July 1, 1936 6 Sheets-Sheet 6 /6Me%/af Patented Mar. 29, 1938 2,112,745 TUNING DIAL FOR RADIO RECEIVING SETS Albert s. ,Wells and Jesse H. Clark, Chicago, m,

assignors to Wells-Gardner & Company, Chica'go, Ill., a corporation of Illinois Application July 1, 1936, Serial No. 88,340

12 Claims.

This invention is concerned with a tuning dial of the screen type onto which may be projected the image of a selected scale. Such a dial is peculiarly suited for radio receiving sets. The

means for operating the present dial is interconnected also with an associated tuning condenser, so as to assure coordinated action therebetween. Our invention is concerned with numerous other features of importance applicable to the tuning dial of a radio receiving set where special conditions obtain. Provision is made, for example, for the transmission of light rays from an illuminant through a light box of sufficient length to prevent distortion of the image which is projected upon the screen and to accomplish this Within a minimum of space and without interference with other operating units in the apparatus. Also as part of this invention we have provided means for operating a slide without lost motion or back lash, whereby the slide may be kept ac curately in step with the tuning condenser whose action is coordinated therewith. Provision is also made for mounting of the tuning dial, together .with its operating mechanism, as a separate unit, and for access to and adjustment or removal of individual parts thereof for purposes of repair or otherwise. In addition, the slide employed in the light projection system is of a character which may be readily changed or replaced, whereby to fit in with the operating mechanism with which it is associated.

With all such objects and purposes our present invention is concerned, as well as with nu- 35 merous other features of advantage, all as will hereinafter appear. Certain suggestive embodiments of our invention are illustrated in the. accompanying drawings, wherein,-

unit in its entirety;

Fig. 2 is a top plan view thereof; Fig. 3 is a vertical section taken through the light box on line 3-3 of Fig. 2;

5 Fig. 4 is a vertical section through the light Fig. 1 is a front elevation of the tuning dial the bearing wherein the slide shaft is rotatably supported; I

Fig. 11 is a view in perspective of the mounting for the projection lens which is arranged between the slide and screen; 5

Fig. 12 is a fragmentary view of the film which is comprised in the slide;

Fig. 13 is a detail in section on line l3 of Fig. 3;

Fig. 14 is a perspective view of the mirror-supl0 porting bracket;

Fig. 15 is a disassembled group view of the parts comprising the mounting for the illuminant;

Fig. 16 is a vertical section through a tuning 15 dial projection apparatus of modified construction;

Fig. 1'7 is a detail of a detent which may be employed for releasably locking the slide shaft in a selected position of longitudinal adjustment, 0 the view being a section taken on line ll of Fig. 16; and

' Fig. 18 is a detail in section taken on line l8 of Fig. 15.

The parts which are special to this invention may be mounted upon a chassis having a base A.

As shown, they are assembled into a separate unit capable of being installed or removed independently of the remaining apparatus with which it is used. In this connection use is made of a frame B in which is mounted a screen C desirably of ground glass, on which is projected an image in the manner to be presently described. Affixed upon the rear side of the frame at each of its ends are pins 20 which enter slots -2l in an elongated plate 22 from which extends lat erally a lug 23 (see Figure 1). A coil spring 24 connects each lug with'a hook 25 adjacent the upper end of the frame whereby to draw the plate to an upper position. A pointer 26 extends laterally from the plate into the field of the screen so as to cast a shadowthereon when there is illumination thereof. Connected with the lug 23 is a flexible cord or wire 21 extending downwardly to a tone-control shaft at having an operating knob (notshown) the position of the pointer being shifted with each actuation of the shaft to afford a visual indication of the tone-control adjustment at all times. A similar pointer mechanism is provided on the opposite end of the frame, operable by a cord or flexible wire 28 from a volume control shaft d having a suitable operating knob (not shown). Connected with this, latter shaft is the usual on and oif switch (not shown).

Extending rearwardly from the frame and connected thereto is a light box Dfihose opposite side walls 36 converge toward the rear end (see Figs. 2, 3 and 4), where one side wall of the light box is cut away and the upper and lower walls 3| thereof are extended laterally to join with an outer side wall 32 extending forwardly at an angle from the rear end of the box. By this construction we provide at the juncture of this outer side wall with the upper and lower walls, a relatively small opening at one side of the light box.

The rearend of the light box may conveniently be supported as by a vertically extending main bracket E (see Fig. whose lower end is afiixed to the chassis base. This bracket, which may serve also as a rear wall for the light box, is provided with a forward extension 36, which, supports a sub-bracket F'having a vertical wall 31 from whose upper end is extended forwardly a horizontal wall 38. Upon the forward side of the main bracket we affix acli p G, held in place as with a screw 4|. As shown in Figs. 2, 3 and 14, the clip comprises a body portion 42 through which the screw is entered, and offset legs 43, 44 and 45 which are spot welded to a plate 46., Bent fingers 41 formed at the edges of this plate cooperate with fingers 48 on the legs 44 and 45 in hooking over the edges of an obliquely disposed mirror 49 which may be slightly adjusted by screws 11 which engage the bifurcated ends of tongues I6 and 19 extending angularly from the plate 46 at points which with the screw form a triangle. A bowed spring 69 is held in position within the plate and bears against the mirror to prevent vibration thereof. Bythe means described, a

three-point mounting for the mirror is provided,

and adjustments thereof may be made from the outside of the light box by manipulation of the protruding ends of the screws. In addition, the lower wall of the light box may be formed with an opening 66 adjacent the mirror, permitting, if desired, application therethrough of a cloth or other implementfor'cleaning and polishing the mirror. The light box is supported at its front end by the frame B which in turn is secured to a further bracket H (see Fig. 6) connected to a mounting plate I, which is afforded a cushioned support by the chassis base.

The forwardly, extending wall 39 of the sub bracket is apertuiged to mount near its front end a depending sleeve 6| provided near its upper end with a. pair of spaced bosses 62 adapted to engage opposite faces of the wall whereby to secure the sleeve in place. Within the sleeve is located a threaded bushing 53 provided at its lower end with a peripheral flange 64 which furnishes ,a bearing for the lower end of a coil spring 56, the upper end of which bears against a cap 66 having a depending flange in which is formed a plurality of bayonet slots 6'! which are adapted to engage a plurality of tongues 69 struck outwardly from the upper margin of the sleeve.

Upon the upper end of the bushing 53 is threaded an adjusting nut 59 which bears against the cap 56 and serves to vertically adjust the bushing against the tension of the coil spring. To the bushing is fixedly secured a socket sleeve 69 having a bayonet slot I6 which is adapted to coact with a stud 16 extending laterally from the neck of an electric lamp J forming the illuminant for the present projecting system. Formed longitu-' dinally upon the exterior surface of the bushing 63 is a'keyway 69 adapted to receive a spline 98 extending inwardly from the cap 56 whereby the rotative portion of the socket 60 is fixed. Vertical adjustments may be performed with the nut 59 without disturbing the rotative portion of the mounting for the illuminant. This is important because the filament of the light bulb which lies in a plane parallel with the bulb axis'should desirably remain always in line with the lens system. By the means just described this result is attained. As clearly shown in Fig. 3, .the'position of this illuminant is opposite the mirror and well toward the front of the light box but exteriorly upon one side thereof. By means of the adjustment provided, the filament of the lamp may be located at the proper level to project the light rays axially through certain lenses presently to be described.

Adjacent the illuminant is an objective lens K mounted in a ring 6| which is supported upon an arm '63 depending from a plate 63 which underlies the horizontal extension wall 38 to which it is adjustably connected as by a screw 64. Pins 65 secured in the plate are adapted to slide within a slot 66 in the plate 38 whereby to assure of adjusting movements in a straight line extending between the illuminant and the mirror. Proximate to the objective lens and supported ad-. justably upon the ring 6| is a cap 61 having an aperture 68 for confining the emission of light rays to a limited area. A second ring 10, carried by the wall 31, is formed with acam slot H for 7 receiving an adjusting pin 12 extended radially from a tube 13 having certain lengthwise slits I4 defining between themspring sections which are urged outwardly to a tight fit within the ring. At the forward end of the tube is mounted a projection lens L. By rotating the adjusting pin within the cam slot the tube is shifted axially whereby to vary the position of theprojection lens. The light rays passing through the objective lens are accordingly confined by its apertured cap to substantially the area of the projection lens from whence they strike the mirror for reflection back to the screen.

Positioned adjacent the illuminant is a slide M. It may be straight, arcuate, or circular. As here shown, it is of the circular type comprising a cylindrical cup 80 of transparent material, such as celluloid, with an apertured bottom wall 8| having arcuate slots 92 at diametrically opposite points through each of which is extended a screw 83 for threaded connection with a bridge plate 64 on which the cup is thereby mounted for rotative adjustment. The circular walls of the cylinder are slightly inset to provide upper and lower shoulders 36 which define between them a recessed area over. which may be affixed a film 96. In the ends of the film are punched holes 81 (see Fig. 7) to receive tines 98 which are extended from a clip 39 by which the film ends are secured together.

The bridge plate is carried fast upon the upper end of a spindle N surrounded by a hub 9| having an elongated slot 92 into which extends a stud 93 projecting radially from the spindle,

there being a leaf spring 94 between the stud and one slot edge of the hub (see Fig. 10). The hub is rotatably mounted in a bearing having at its upper end a head 96 which is carried upon a shelf 91 extending laterally from .the upper end forming a pulley around which may be coiled one cured whereby to exert both compressive and torsional forces which are transmitted to the slide in all its positions of adjustment. The action of this spring supplements that of the spring 64 to prevent back lash or lost motion in the operative connections to the slide. The cord, I66 is trained over an/adia'cent pulley I01 carried on one end of a swihging arm I06 having a pivotal mounting at III 9, there being a spring IIO connecting the opposite arm end with a lug III which extends laterally from the bracket H. Continuing, the

- cord passes over a pulley II2 carried fast on a luminant for the projection of images upon the shaft H3 in operative connection with a series of plates forming part of a tuning mechanism 0.

This shaft, which extends horizontally below the light box, carries a second pulley H4. The belt I06 may pass over a further guiding idler -I I5 before returning to the pulley I06. Trained over the pulley H4 is a second belt I26 engaged by a tensioning idler I2I and passing around a driving pulley I22 which is carried fast on the tuning control shaft 0. By rotation of an operating knob (not shown) amxed to the shaft 0 the belt is actuated to rotate the shaft I I3, which through the medium of the belt I06 imparts rotation to the spindle whereon is carried the rotatable slide. Near the lower end of thespindle is an annular groove I25 with which engages a yoke I26 pivotally supported at I21 near'one end of a rocking arm I26 having an adjustable pivotal mounting I29 (see Fig. 1). Near the opposite arm end which lies adjacent the bracket H is a detent which may comprise a ball I30 confined in part within a socket therein, the projecting surface of the ball lying opposite a series of openings I 3| in the bracket in any one of which the ball may partly enter. The arm I28 may, accordingly be rocked about its pivot I29 to raise or lower the yoke, and with it the spindle and cylindrical slide. As shown, the bracket is provided with three slots I3I, thus providing a corresponding number of positions in which the rockable arm may be releasably secured. From the arm end opposite that whereon the yoke is attached depends a link I35 connected thereto at I36, this link having a pivotal connection I31 with,a crank I38 that is mounted fast upon a shaft b having connection,

if desired, with gang switches in accordance with usual practice. By rotation of this shaft, as throughthe medium of an operating knob (not shown) the rocking arm is actuated to shift the cylindrical slide axially to any of three positions in each of which it is releasably locked by the detent mechanism.

With a light projecting apparatus, as herein shown, it .is possible to utiliz any selected film with the slide. The film may be removed and a new one substituted if this be desired. Each film is desirably provided with three scales of indications (see Fig. 12) arranged circumferentially of the cylinder. The positions of these scales are such that but one of them will lie in the path of the confined light rays emanating from the ilscreen. The detent mechanism is so arranged that any selected scale may be positioned in the path of the light rays, and further adjustment to assure exact framing is provided by the pivot bolt I26, which, as best shown in Fig. 9, is extended.

through a vertical slot I46 in the bracket-H, and

then through a disk in having a hub. I42 which fits within an opening in the rocking arm m,

there being a washer I43 at the end of the hub against which pressure is exerted by a nut I44 which is screw threaded upon the bolt. By some such pivotal connection as this, the rocking point of the arm may be vertically adjusted whenever required for correct framing of the film scales upon the screen. In practice, the scales will desirably display indications applying to high wave, low wave and medium wave reception.

If desired, a multi-color screen may be interposed in the light rays, preferably at a point between the slide and projection lens. As indicated in Figs. 3 and 13, such a screen may employ a.

quadrant frame 33 disposed in a vertical plane and pivoted as at 34 to a-post 35 which is extended laterally from the sub-bracket wall 31. A lug 39 extended horizontally from the frame at a point removed from its pivotal mounting,

engages the slide bottom againstwhich it is constantly held by the tension of a spring 40 coiled around the post' withmne end secured to the frame, and the other to the wall 31. As the slide is shifted vertically into one of its three po-' sitions the screen frame is rocked in consequence so as to present in the path oflight beams one of three openings at, y and z in the frame. In each of these openings, if desired, is mounted a trans parency of individual color so as to produce upon the screen a separate color for eachof the image scales that is projected from the slide. This change in color which takes place automatically with each vertical shift in the position of the slide, continues for all images that are projected from a selected object area of the slide. Accordingly, we have provided for a changeable dial a changeable color system which produces a distinctive color for each scale of the dial that is exhibited.

It is important that there be no lost motion in the transmission between the operating shaft and the cylindrical slide, so that the position of the objects projected therefrom upon the screen will always be coordinated with that of the tuning mechanism. An initial adjustment of the cylindrical slide may be made by loosening the screws 83 which connect the cup bottom 8| to the bridge. plate, and then shifting the one rotatably with respect to the other to the desired position, after which the screws are again tightened. The driving force applied by the belt I06 to the pulley "i5 is transmitted without loss of motion through the hub with associated leaf spring 94 to the'stud 93 which extends laterally from the spindle. The belt, which may be coiled around the pulley one or more times to obviate any possibility of slip-- dial of the light projecting type is that the slide. ..may carry an extensive amount of indicia of which any selected part may be projected for magnified display over the entire surface of a relatively small screen. It is accordingly possible to display data and words considerable in amount, and by rotating theslide to bring into view an entire new display of data and words legibly exhibited upon .the screen.

The mechanism thus far described involves a light projecting system in which is incorporated a mirror whereby to obtain greater distance between the illuminant and the screen. It is possible to utilizea iight-proirncting apparatus in showna light box Dwhose front end is affixed to and carried bya-supporting bracket I45 on which i'salsosupported the screen C. The four sides ofithis box converge to form a truncated py amid having an open rear end adjacent va-projection lens Lsuppo'rted'in 'a tube. I41 which is adjustably fitted within a sleeve-I28 having a mounting ina wall I49 forming part of a main bracket P,

' in which is alsooomprised a horizontal wall I50 and a rearward depending wall I5I. Mounted on y the bracket is a sub-bracket Q slidably secured I60 surrounding the circular wall I6I of a trans-' as by a screw I52 which connects with the horizontal wall of the main bracket, the screw being positioned in a slot I53 in the sub-bracket which permits the latter to be shifted forwardly or rearwardly as required.

From the depending wall 'I 3 Iis supported a ring I55 wherein is mounted anobjective lens K in proximity to an illuminant 'J inthe form of a light bulb which depends from a socket I59 having a mounting in the sub-bracket. Both the illuminant and objective lens are positioned within a cylindrical slide M which may comprise'a film parent cup I62 whose bottom is adjustably secured to a bridge plate I63 affixed to the upper end of a spindle N. Below the bridge plate is a chambered ring I65 from which depends a tail I66 which lies within the slot of a lug- I 61 extending laterallyfrom a block I68 having a-fixed mounting to support a bearing I69 into which the spindle is rotatably fitted. Formed in this spindle is a longitudinal slot I10 into which is fitted a key (not shown) extending inwardly from a beveled gear "I which is slidably fitted upon the spindle. A second beveled gear I12 in mesh with the first is affixed to one end of a tuning control shaft I13 on whose opposite end is a pulley I14 over which is trained a belt I15 which passes over a second pulley I16 on one end of a shaft 0. By the connections described, the shaft 0 may be actuated to rotate the cylindrical slide whereby to cause projection therefrom' of an image upon the screen whereby it is magnitied for legible display.

The ring I65, as shown in Fig. 18, accommodates a coiled spring I having one end I8I anchored to the spindle, its opposite end I82 being connected to the ring adjacent its tail I66. There is thus maintained a constant one-way rotational force upon the spindle, which obviates any lost motion which might otherwise occur during periods of operation.

The cylindrical slide together with the spin die on which it is mounted is adapted for axial adjustment, three positions being indicated. To accomplish this we have formed in the spindle adjacent its lower end an annular groove I85 wherein is received a pin I86 which is extended from one end of a rocking arm I81 having a pivotal mounting at I88 (see Fig. 17). This arm constitutes a lateral turned end of a bar I 90 actuated whereby the pin I66 willcause the spin';

die to move up or down. The end of the arm I81 (see Fig. 17) may be tapered off to provide a finger I adapted to engage successively with three notches I96 formed in a swinging arm l9 1,pi,vot-

ally mounted at I98 and heldby a spring I99 at its opposite end in constant engagement'with the finger. This mechanism constitutes -a simple form of 'detent which will sustain the spindle and 5 cylindrical slide in any of the three adjusted axial positions that are provided. I The mechanism of'Figs. 16, 1'7 and 1 8.is.in' "g'eneralthe same in operation as-that already -described in the remaining figures of thegdrawings. There is this primary difference, however," and thatis the light projecting apparatus operates directly insteadv of indirectly with the aid. of a mirror. Other points of' distinction areof less importance. It may bethat more space will be required for the installation of this direct type of projection apparatus in order to providebetween the. illuminant and screen sufllcient distance to obviate distortion of the projected images. We would have it understood, therefore, that either type may be employed,'depending upon the particular conditions of use. v,

One important feature of :our inventionresides in utilization of a light projection system which comprises a'box from which outside light is excluded. The small aperture adjacent the mirror or illuminant permits the latter to be located outside of the box; yet it concentrates its light rays passing through the objective lens to an area no larger than the light box aperture through which these rays pass to reach the screen.

The slide is, furthermore, positioned exteriorly of the box and by reason of its cup-like form may surround the illuminant and yet remain cool because of its open top and the ventilating openings through its bottom. These features of advan from different scales of a dial, render the entire apparatus particularly suitablefor use with the tuning mechanism of a radio receivingset. The movements of the dial are carefully coordinated with those of the tuning mechanism, through connections which maybe adjusted and which function without any loss of motion. All such improvements contribute to the satisfactory operation-of a tuning mechanism incorporating the principles of invention as hereinbefore described and particularly pointed out in the appended claims, as follows:

We claim: v

1. In a radio receiving set, the combination with a tuning mechanism of a light projection system comprising an illuminant, a movable slide and a screen all aligned in the order named, and a rotable connection between the tuning mechaiism and slide in which the slide is also longitudinally movable, and said conection including a tension device to prevent lost lateral motion and preserve coordination in the movements of the tuning mechanism and slide.

2.-In a radio receiving set, the combination with .a tuning mechanism, of a light projection system comprising an illuminant, a screen and a circular slide between the illuminant and screen,

the slide having circumferentially extending mul- 1 of two paths whereby to cause projection upon the screen of objects from only a selected area of the slide, a color screen movably mounted in the path of light projection, and means connecting the screen with the slide for movement therewith through one path of movement of the latter, said means cooperating with means on the slide to hold said color screen stationary while said slide is being moved through its other path of movement.

14. In a radio receiving set, a tuning mechanism comprising a light projection system in which is an illuminant, a cylindrical slide mounted for rotary and reciprocatory movements, a

multi-color screen, a screen onto which images may be projected from the slide, means mounting the color screen for movement through a vertical plane adjacent the periphery of said cylindrical slide, and means forming an operating connection between said slide and color screen when said slide is reciprocated and'a holding means tor said color screen when said slide is.

rotated.

5. In a radio receiving set, a tuning mechanism comprising a light projection system in which is an illuminant, a, slide mounted for movement in two directions relative to its mounting, "a color screen, an image screen onto which images may be projected from the slide through said color screen, and means holding the slide and color screen in frictional engagement for concurrent movement in but one of the directions of movement of said slide.

6. In a gradio receiving set, a changeable station indicating mechanism in which is comprised a screen and a cylindrical longitudinally shiftable indicating scale, a multi-color screen pivotally mounted adjacent the periphery of said cylindrical scale, said screen having'an oflfset arm adapted to extend into the longitudinallyshiftable path of movement of said scale, means holding said arm and scale ,in frictional engagement,

and means for rotating and longitudinally shitting said scale to position a selected portion thereof in a distinctive color upon the screen of the station indicating mechanism.

7. In a radio receiving set, the combination with a tuning mechanism or a light projection system comprising an illuminant, a slide and a screen in operative relation, means for shifting the slide through either of two movement paths, and operative connections between the tuning mechanism and slide for shiiting the slide through one of its movement paths, said con-' nection including tension means to prevent lateral lost motion of the slide relative to the connections when traversing either of its movement paths wherebyto preserve co-ordination in the movements of the tuning mechanism and slide.

8. In a radio receiving 'set, a light projection system in which is a light box, a screen and a mirror mounted in spaced relation in the light box, an illuminant and a station indicator slide mounted for vertical and horizontal movements exteriorly of the light box, and means exteriorly of the box in connection with the mirror for adjusting its angular position within the box with relation to a selected portion of said slide and .screen in both vertical and horizontal directions.

9. In a radio receiving set, a light projection system comprising -a screen, a mirror, an illuminant and a slide in operative relation, and a three-point adjustable mounting for the mirror. 10. In a radio receiving set, the combination with a tuning mechanism and an image screen for the receiving set, a light box extending into the receiving set from said image screen, means fixedly supporting said light box and adjustably supporting an illuminant and lens system adjacentthe inner end of said light'box, a color screen and a slide each having multiple projection areas supported by said means for relative movements through the focal path of said lens system,'means for relatively positioning the lens system, slide and image. screen to project upon the latter through different areas of the cdlor screen objects from different areas of the'slide, means for advancing the slide through. a fixed path of movement such as to project through a single area of the color screen only objects from a selected area of the slide, and operative connections between said means and said tuning mechanism.

11. In a radio receiving set, a tuning mechanism comprising a light projecting system in which is a light box, an image screen at one end of the box, a color screen at the opposite end of the box, an illuminant positioned to direct rays through the color screen andbox onto the. image screen, a slide interposed in the light rays between the illuminant and color screen,

and means for producing relative movement beend or the light box, a support extending rear wardly from said light'box, an illuminant and lens system suspended from said support and positioned to direct concentrated rays through I the light box onto the screen, a'slide also mount,-

ed-on said supportto extend intothellshtrays of said light projecting system, and means providing a pivotal mounting onsaid bracket and operatively connected to .said tuning ,dnechanism for producing relative vertical" and horizontal-movements of said slide and light pm- I jecting system.

smna'r s. warms.

mssncmnx. 

